US6707592B1 - Optical switch with static bubble - Google Patents

Optical switch with static bubble Download PDF

Info

Publication number
US6707592B1
US6707592B1 US10/288,675 US28867502A US6707592B1 US 6707592 B1 US6707592 B1 US 6707592B1 US 28867502 A US28867502 A US 28867502A US 6707592 B1 US6707592 B1 US 6707592B1
Authority
US
United States
Prior art keywords
bubble
switching chamber
static
static bubble
optical switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US10/288,675
Inventor
Dale W. Schroeder
John J. Uebbing
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Avago Technologies International Sales Pte Ltd
Original Assignee
Agilent Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Agilent Technologies Inc filed Critical Agilent Technologies Inc
Priority to US10/288,675 priority Critical patent/US6707592B1/en
Assigned to AGILENT TECHNOLOGIES, INC. reassignment AGILENT TECHNOLOGIES, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: UEBBING, JOHN J., SCHROEDER, DALE W.
Application granted granted Critical
Publication of US6707592B1 publication Critical patent/US6707592B1/en
Assigned to AVAGO TECHNOLOGIES GENERAL IP PTE. LTD. reassignment AVAGO TECHNOLOGIES GENERAL IP PTE. LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AGILENT TECHNOLOGIES, INC.
Assigned to AVAGO TECHNOLOGIES FIBER IP (SINGAPORE) PTE. LTD. reassignment AVAGO TECHNOLOGIES FIBER IP (SINGAPORE) PTE. LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.
Assigned to AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD. reassignment AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD. CORRECTIVE ASSIGNMENT TO CORRECT THE NAME OF THE ASSIGNEE PREVIOUSLY RECORDED ON REEL 017207 FRAME 0020. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT. Assignors: AGILENT TECHNOLOGIES, INC.
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/004Optical devices or arrangements for the control of light using movable or deformable optical elements based on a displacement or a deformation of a fluid
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/3538Optical coupling means having switching means based on displacement or deformation of a liquid
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/351Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3522Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element enabling or impairing total internal reflection
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/354Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/35442D constellations, i.e. with switching elements and switched beams located in a plane
    • G02B6/3546NxM switch, i.e. a regular array of switches elements of matrix type constellation
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/3564Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/3576Temperature or heat actuation

Definitions

  • the present invention relates to optical switches and more particularly to bubble optical switches.
  • Optical communication networks use optical waveguides to transmit optical signals representing data.
  • optical switches are used to route optical signals from one waveguide to another.
  • One type of optical switch uses fluids and vapor bubbles to switch optical signals. This type of switch is often referred to as a bubble switch.
  • trenches are formed where the waveguides intersect and are filled with an index matching fluid, the index matching fluid having refractive index that is the same as the refractive index of the optical waveguides.
  • a bubble switch In an inactive state, a bubble switch includes a trench filled with index matching fluid. Because the index matching fluid has the same refractive index as the waveguide segments that intersect that the bubble switch, no switching is performed at the switch. That is, an optical signal from a first waveguide segment enters the fluid filled trench, passes straight through the fluid-filled trench, and enters a second waveguide segment.
  • heat is applied to nucleate a bubble within the trench. The bubble displaces the fluid within the trench and fills the trench with vapor.
  • the vapor has a refractive index that is close to one. Accordingly, the optical signal from the first waveguide is reflected at the wall of the vapor-filled trench and enters a third waveguide segment.
  • heat is removed from the switch allowing the bubble to collapse and the index matching fluid to again fill the trench.
  • the portion of the trench wherein the bubble displaces the index matching fluid is often referred to as a switching chamber.
  • the bubble For fast switch activation, the bubble must be nucleated quickly. This requires application of high temperature to the switch to quickly bring the index matching fluid to a boil to create vapor for the bubble. For example, for some index matching fluid,.temperatures of up to 225 degrees Celsius are required for nucleation. Once the bubble is nucleated, it can be maintained at a lower temperature such as 100 degrees Celsius. The high temperature required for nucleation stresses the bubble switch thus reduces the lifetime and reliability of the switch.
  • the bubble For fast switch deactivation, the bubble must be completely collapsed within the index matching fluid. However there is often air or other gaseous impurities in the fluid. These impurities must dissolve back into the fluid. The dissolution process is often inconsistent, leaving residual bubbles for 30 milliseconds or more. This causes disturbance in the path of optical signals and an inconsistent switch turn off time.
  • an optical switch includes a static bubble drum and a switching chamber.
  • the static bubble drum is adapted to contain a static bubble.
  • the switching chamber is adapted to allow the static bubble to expand into it from the static bubble drum.
  • each optical switch in a plurality of optical switches includes a static bubble drum and a switching chamber.
  • the static bubble drum is adapted to contain a static bubble.
  • the switching chamber is adapted to allow the static bubble to expand into it from the static bubble drum.
  • Each optical switch in the plurality of optical switches also includes a heater that is proximal to the static bubble drum, switching chamber, or both.
  • a method for switching optical signal includes applying heat to a static bubble drum. The heat expands a static bubble from the drum into a switching chamber.
  • FIG. 1 is a simplified cutaway top view of an optical switch array according to one embodiment the present invention
  • FIG. 2A is a top view of a first optical switch of the optical switch array of FIG. 1 in an inactive state
  • FIG. 2B is a top view of the first optical switch of the optical switch array of FIG. 1 in an active state
  • FIG. 3 is a cutaway side view of the first optical switch of FIG. 2 A.
  • the present invention is embodied in an optical switch containing fluid with a switching chamber connected to a static bubble drum.
  • the static bubble drum contains a static bubble that remains in the drum during the switch's inactive or off state.
  • the bubble drum is heated thereby expanding the bubble into the switching chamber.
  • the heat is removed, thereby allowing contraction of the expanded bubble into the static bubble drum.
  • a temperature that is lower than the nucleation temperature can be used to activate the switch because it is not necessary to form or nucleate the bubble from the fluid. Therefore, the reliability of the optical switch is improved because lower temperatures are used.
  • the bubble is contracted rather than totally dissolved to deactivate the switch thereby increasing the deactivation speed of the switch.
  • An additional advantage of the present invention is the reduction of hydrodynamic cross talk.
  • An optical switching array includes an array of bubble switches interconnected via a common fluid filled layer including index matching fluid. Because the switches are connected via the common fluid layer, in the prior art designs, turning switches on or off (by nucleating or collapsing bubbles) introduces sharp pressure waves within the fluid filled layer, the pressure waves having a relatively high peak pressure. The sharp pressure waves travel within the fluid filled layer causing hydrodynamic cross talk between the bubble switches within the optical switching array.
  • Such cross talk is alleviated in the present invention because the on and off operations of the bubble switch are performed by expansion and contraction of the static bubble. These operations introduce significantly lower peak pressure that affects the other switches within the switching array.
  • FIG. 1 an optical switch array 100 according to one embodiment of the present invention is illustrated. For simplicity, only two switches are illustrated therein.
  • a first optical switch 102 is illustrated at a first state referred to as an inactive state.
  • a second optical switch 202 is illustrated at a second state referred to as an active state.
  • FIG. 2A illustrates a top view of the first optical switch 102 in the inactive state.
  • the first optical switch 102 of FIG. 2A is also referred to as an inactive optical switch 102 .
  • the inactive optical switch 102 includes a switching chamber 126 , or a trench, filled with index matching fluid. Portion of the trench whereat optical signals from the waveguide segments 110 - 116 are reflected is generally referred to as the switching chamber 126 .
  • the switching chamber 126 can be approximately 15 microns in width 127 .
  • a static bubble drum 124 is connected to the switching chamber 126 . In one embodiment, the static bubble drum 124 can be approximately 40 microns in diameter 125 .
  • the static bubble drum 124 is adapted to contain an inactive static bubble 122 .
  • the static bubble drum 124 is able to contain the static bubble 122 because the surface tension generates pressure across the bubble-liquid interface proportional to ⁇ /r bub , where ⁇ is the surface tension and r bub is the radius of the bubble.
  • the static bubble drum 124 has a diameter 125 that is greater than the width 127 of the switching chamber 126 , and the pressure difference between the index matching fluid and the inside of the bubble is not enough to collapse the status bubble 122 in the static bubble drum 124 .
  • the size, or width 127 , of the switching chamber 126 is smaller than the diameter 125 of the bubble drum 124 , and surface tension induced pressure from the index matching fluid will collapse a bubble (were it to form within the switching chamber 126 ) in the absence of additional pressure within the bubble generated by heat. Heat raises the bubble temperature and this raises the pressure within the bubble by way of the increased vapor pressure.
  • the inactive optical switch 102 allows an optical signal 118 to traverse straight through the switching chamber 126 from a first waveguide segment 110 to a second waveguide segment 114 .
  • the optical signal within the second waveguide segment 114 is illustrated as a non-switched optical signal 119 .
  • the static bubble drum 124 , the switching chamber 126 , or both are heated causing the static bubble 122 to expand into the switching chamber 126 .
  • the heat increases the bubble temperature and increases the evaporation of heated fluid.
  • the fluid vapor pressure increases with temperature. This higher pressure is enough to overcome the surface tension forces that keep the static bubble 122 in the static bubble drum 126 .
  • the static bubble 122 then expands into the switching chamber 126 .
  • the expanded bubble 122 x also referred to as an active bubble 122 x, is illustrated in FIG. 2 B.
  • the temperature required to expand the inactive static bubble 122 into the switching chamber 126 is less than the temperature required to nucleate a bubble from the index matching fluid.
  • a temperature of 100 degrees Celsius may be sufficient to expand the static bubble 122 whereas a homogeneous nucleation temperature of 225 degrees Celsius may be needed to create a bubble.
  • less heat and less stress are applied to the switch 102 thereby increasing the lifetime and reliability of the switch 102 .
  • some of the components of the switch 102 such as a pillow, are less likely to deteriorate from excessive heat otherwise required to nucleate the bubble from the index matching fluid.
  • the switching chamber 126 is adapted to allow the inactive static bubble 122 to expand into it from the static bubble drum 124 .
  • the first optical switch 102 in FIG. 1 is illustrated in the active or on state.
  • the optical switch in FIG. 2B is referred to as an active optical switch 102 x herein.
  • the active optical switch 102 x is illustrated having a similar structure as the inactive optical switch 102 of FIG. 2 A.
  • the configuration and the dimensions of the active optical switch 102 x are generally similar to the corresponding portions of the inactive optical switch 102 including the switching chamber 126 , the static bubble drum 124 , and a quenching pipe 128 .
  • the active bubble 122 x fills the switching chamber 126 with vapor.
  • the refractive index of the vapor within the active bubble 122 x is nearly equal to one.
  • the active optical switch 102 x reflects, or switches, the optical signal 118 from the first waveguide segment 110 to a third waveguide segment 116 .
  • the reflected optical signal is illustrated as a switched signal 120 .
  • the heat is removed allowing the active optical switch 102 x to cool.
  • surface tension forces the active bubble 122 x to contract away from the switching chamber 126 into the static bubble drum 124 .
  • the index matching fluid rushes into the switching chamber 126 to fill the space being vacated by the contracting bubble.
  • the switching chamber 126 is connected to a quenching pipe 128 providing additional paths for the index matching fluid to enter the switching chamber 126 .
  • the quenching pipe 128 is approximately 15 microns in diameter 129 .
  • the quenching pipe 128 facilitates replacing the space within the switching chamber 126 (vacated by the contracting active bubble 122 x ) with the index matching fluid.
  • the active bubble 122 x contracts and eventually resembles the inactive static bubble 122 of FIG. 2 A.
  • the active bubble 122 x need not collapse completely in order to deactivate the switch 102 x. Accordingly, the deactivation of the active switch 102 x is accomplished more quickly than in prior art. Further, no residual air bubbles are formed because the bubble, when contracting, holds all the vapor and residual air.
  • the switching chamber 126 is again filled with the index matching fluid allowing the first optical signal 118 to pass directly through the switching chamber 126 as illustrated in FIG. 2 A.
  • FIG. 3 is a cutaway side view of the inactive optical switch 102 of FIG. 2A along line A—A.
  • the inactive optical switch 102 has a bottom layer 106 as a substrate, typically made of silicon.
  • a bottom integrated circuit (IC) passivation layer 130 is fabricated over the substrate 106 .
  • the bottom IC passivation layer 130 can be fabricated from silicon dioxide.
  • a heater 132 is typically fabricated within the bottom IC passivation layer 130 .
  • the heater 132 can be buffered by a pillow 134 as illustrated.
  • the pillow 134 made of for example gold, buffers the heat generated by the heater 132 .
  • the heater 132 and the pillow 134 are proximal to the static bubble drum 124 , the switching chamber 126 , or both.
  • the heater 134 provides heat to the static bubble drum 124 , the switching chamber 126 , or both, the heat causing the expansion of the inactive static bubble 122 as discussed herein above.
  • the switching chamber 126 , the static bubble drum 124 , and the quenching pipe 128 are generally located above and connected to a fluid filled layer 136 .
  • the index matching fluid is generally present in these chambers except as displaced by the inactive static bubble 122 .
  • the static bubble drum 124 contains the inactive static bubble 122 , therefore a majority of the fluid within the static bubble drum 124 is displaced by the static bubble 122 .
  • the static bubble drum 124 and the switching chamber 126 are filled with the active bubble 122 x of FIG. 2B.
  • a top structural layer 138 covers and encloses the switch 102 .
  • this layer 138 can be fused silica.

Abstract

A bubble optical switch includes a switching chamber, a static bubble drum, and a quenching pipe. The static bubble drum is adapted to contain a static bubble. In the inactive state, the static bubble remains within the static bubble drum and the switching chamber is filled with index matching fluid. To activate the switch, heat is introduced expanding the static bubble into the switching chamber displacing the index matching fluid with vapor. Then, the optical signal is reflected from the wall of the switching chamber. When the heat is removed, the static bubble contracts back into the static bubble drum. Because the temperature required to expand the static bubble is lower than the temperature required to nucleate a bubble from the fluid, the reliability and lifetime of the switch is increased. Further, due to the properties of the contracting static bubble, no residual bubble forms, thereby alleviating problems associated with residual bubbles of the prior art bubble switches.

Description

BACKGROUND
The present invention relates to optical switches and more particularly to bubble optical switches.
Optical communication networks use optical waveguides to transmit optical signals representing data. At various points along the network, optical switches are used to route optical signals from one waveguide to another. One type of optical switch uses fluids and vapor bubbles to switch optical signals. This type of switch is often referred to as a bubble switch. In this design, trenches are formed where the waveguides intersect and are filled with an index matching fluid, the index matching fluid having refractive index that is the same as the refractive index of the optical waveguides.
In an inactive state, a bubble switch includes a trench filled with index matching fluid. Because the index matching fluid has the same refractive index as the waveguide segments that intersect that the bubble switch, no switching is performed at the switch. That is, an optical signal from a first waveguide segment enters the fluid filled trench, passes straight through the fluid-filled trench, and enters a second waveguide segment. To activate the bubble switch, heat is applied to nucleate a bubble within the trench. The bubble displaces the fluid within the trench and fills the trench with vapor. The vapor has a refractive index that is close to one. Accordingly, the optical signal from the first waveguide is reflected at the wall of the vapor-filled trench and enters a third waveguide segment. To inactivate the bubble switch, heat is removed from the switch allowing the bubble to collapse and the index matching fluid to again fill the trench. The portion of the trench wherein the bubble displaces the index matching fluid is often referred to as a switching chamber.
For fast switch activation, the bubble must be nucleated quickly. This requires application of high temperature to the switch to quickly bring the index matching fluid to a boil to create vapor for the bubble. For example, for some index matching fluid,.temperatures of up to 225 degrees Celsius are required for nucleation. Once the bubble is nucleated, it can be maintained at a lower temperature such as 100 degrees Celsius. The high temperature required for nucleation stresses the bubble switch thus reduces the lifetime and reliability of the switch.
For fast switch deactivation, the bubble must be completely collapsed within the index matching fluid. However there is often air or other gaseous impurities in the fluid. These impurities must dissolve back into the fluid. The dissolution process is often inconsistent, leaving residual bubbles for 30 milliseconds or more. This causes disturbance in the path of optical signals and an inconsistent switch turn off time.
Consequently, there remains a need for an improved bubble optical switch that alleviates these shortcomings.
SUMMARY
The need is met by the present invention. According to one aspect of the present invention, an optical switch includes a static bubble drum and a switching chamber. The static bubble drum is adapted to contain a static bubble. The switching chamber is adapted to allow the static bubble to expand into it from the static bubble drum.
According to another aspect of the present invention, each optical switch in a plurality of optical switches includes a static bubble drum and a switching chamber. The static bubble drum is adapted to contain a static bubble. The switching chamber is adapted to allow the static bubble to expand into it from the static bubble drum. Each optical switch in the plurality of optical switches also includes a heater that is proximal to the static bubble drum, switching chamber, or both.
According to yet another aspect of the present invention, a method for switching optical signal includes applying heat to a static bubble drum. The heat expands a static bubble from the drum into a switching chamber.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified cutaway top view of an optical switch array according to one embodiment the present invention;
FIG. 2A is a top view of a first optical switch of the optical switch array of FIG. 1 in an inactive state;
FIG. 2B is a top view of the first optical switch of the optical switch array of FIG. 1 in an active state; and
FIG. 3 is a cutaway side view of the first optical switch of FIG. 2A.
DETAILED DESCRIPTION
As shown in the exemplary drawings and discussed herein below, the present invention is embodied in an optical switch containing fluid with a switching chamber connected to a static bubble drum. The static bubble drum contains a static bubble that remains in the drum during the switch's inactive or off state. To activate or turn on the switch, the bubble drum is heated thereby expanding the bubble into the switching chamber. To deactivate or turn off the switch, the heat is removed, thereby allowing contraction of the expanded bubble into the static bubble drum. A temperature that is lower than the nucleation temperature can be used to activate the switch because it is not necessary to form or nucleate the bubble from the fluid. Therefore, the reliability of the optical switch is improved because lower temperatures are used. Furthermore, the bubble is contracted rather than totally dissolved to deactivate the switch thereby increasing the deactivation speed of the switch.
An additional advantage of the present invention is the reduction of hydrodynamic cross talk. An optical switching array includes an array of bubble switches interconnected via a common fluid filled layer including index matching fluid. Because the switches are connected via the common fluid layer, in the prior art designs, turning switches on or off (by nucleating or collapsing bubbles) introduces sharp pressure waves within the fluid filled layer, the pressure waves having a relatively high peak pressure. The sharp pressure waves travel within the fluid filled layer causing hydrodynamic cross talk between the bubble switches within the optical switching array. Such cross talk is alleviated in the present invention because the on and off operations of the bubble switch are performed by expansion and contraction of the static bubble. These operations introduce significantly lower peak pressure that affects the other switches within the switching array.
In FIG. 1, an optical switch array 100 according to one embodiment of the present invention is illustrated. For simplicity, only two switches are illustrated therein. A first optical switch 102 is illustrated at a first state referred to as an inactive state. A second optical switch 202 is illustrated at a second state referred to as an active state. FIG. 2A illustrates a top view of the first optical switch 102 in the inactive state. For purposes of discussion, the first optical switch 102 of FIG. 2A is also referred to as an inactive optical switch 102.
Referring to FIGS. 1 and 2A, a first set of waveguide segments 110-116 intersect at the inactive optical switch 102. The inactive optical switch 102 includes a switching chamber 126, or a trench, filled with index matching fluid. Portion of the trench whereat optical signals from the waveguide segments 110-116 are reflected is generally referred to as the switching chamber 126. In one embodiment, the switching chamber 126 can be approximately 15 microns in width 127. A static bubble drum 124 is connected to the switching chamber 126. In one embodiment, the static bubble drum 124 can be approximately 40 microns in diameter 125. The static bubble drum 124 is adapted to contain an inactive static bubble 122.
The static bubble drum 124 is able to contain the static bubble 122 because the surface tension generates pressure across the bubble-liquid interface proportional to σ/rbub, where σ is the surface tension and rbub is the radius of the bubble. The static bubble drum 124 has a diameter 125 that is greater than the width 127 of the switching chamber 126, and the pressure difference between the index matching fluid and the inside of the bubble is not enough to collapse the status bubble 122 in the static bubble drum 124. In the switching chamber 126, however, the size, or width 127, of the switching chamber 126 is smaller than the diameter 125 of the bubble drum 124, and surface tension induced pressure from the index matching fluid will collapse a bubble (were it to form within the switching chamber 126) in the absence of additional pressure within the bubble generated by heat. Heat raises the bubble temperature and this raises the pressure within the bubble by way of the increased vapor pressure.
In the inactive state, the static bubble 122 remains in the static bubble drum 124 and the switching chamber 126 is filled with the index matching fluid. Thus, the inactive optical switch 102 allows an optical signal 118 to traverse straight through the switching chamber 126 from a first waveguide segment 110 to a second waveguide segment 114. The optical signal within the second waveguide segment 114 is illustrated as a non-switched optical signal 119.
To activate the inactive optical switch 102, the static bubble drum 124, the switching chamber 126, or both are heated causing the static bubble 122 to expand into the switching chamber 126. The heat increases the bubble temperature and increases the evaporation of heated fluid. The fluid vapor pressure increases with temperature. This higher pressure is enough to overcome the surface tension forces that keep the static bubble 122 in the static bubble drum 126. The static bubble 122 then expands into the switching chamber 126. The expanded bubble 122 x, also referred to as an active bubble 122 x, is illustrated in FIG. 2B. The temperature required to expand the inactive static bubble 122 into the switching chamber 126 is less than the temperature required to nucleate a bubble from the index matching fluid. For example, a temperature of 100 degrees Celsius may be sufficient to expand the static bubble 122 whereas a homogeneous nucleation temperature of 225 degrees Celsius may be needed to create a bubble. As a result, less heat and less stress are applied to the switch 102 thereby increasing the lifetime and reliability of the switch 102. For example, some of the components of the switch 102, such as a pillow, are less likely to deteriorate from excessive heat otherwise required to nucleate the bubble from the index matching fluid. The switching chamber 126 is adapted to allow the inactive static bubble 122 to expand into it from the static bubble drum 124.
Referring to FIG. 2B, the first optical switch 102 in FIG. 1 is illustrated in the active or on state. For purposes of discussion, the optical switch in FIG. 2B is referred to as an active optical switch 102 x herein. The active optical switch 102 x is illustrated having a similar structure as the inactive optical switch 102 of FIG. 2A. The configuration and the dimensions of the active optical switch 102 x are generally similar to the corresponding portions of the inactive optical switch 102 including the switching chamber 126, the static bubble drum 124, and a quenching pipe 128.
In the active state, the active bubble 122 x fills the switching chamber 126 with vapor. As already discussed, the refractive index of the vapor within the active bubble 122 x is nearly equal to one. Thus, the active optical switch 102 x reflects, or switches, the optical signal 118 from the first waveguide segment 110 to a third waveguide segment 116. The reflected optical signal is illustrated as a switched signal 120.
To deactivate the active optical switch 102 x, the heat is removed allowing the active optical switch 102 x to cool. As the temperature and thus the pressure in the bubble decreases, surface tension forces the active bubble 122 x to contract away from the switching chamber 126 into the static bubble drum 124. When the expanded bubble 122 x contracts, the index matching fluid rushes into the switching chamber 126 to fill the space being vacated by the contracting bubble.
The switching chamber 126 is connected to a quenching pipe 128 providing additional paths for the index matching fluid to enter the switching chamber 126. In one embodiment, the quenching pipe 128 is approximately 15 microns in diameter 129. The quenching pipe 128 facilitates replacing the space within the switching chamber 126 (vacated by the contracting active bubble 122 x) with the index matching fluid. The active bubble 122 x contracts and eventually resembles the inactive static bubble 122 of FIG. 2A.
The active bubble 122 x need not collapse completely in order to deactivate the switch 102 x. Accordingly, the deactivation of the active switch 102 x is accomplished more quickly than in prior art. Further, no residual air bubbles are formed because the bubble, when contracting, holds all the vapor and residual air. The switching chamber 126 is again filled with the index matching fluid allowing the first optical signal 118 to pass directly through the switching chamber 126 as illustrated in FIG. 2A.
FIG. 3 is a cutaway side view of the inactive optical switch 102 of FIG. 2A along line A—A. Referring to FIGS. 2A and 3, the inactive optical switch 102 has a bottom layer 106 as a substrate, typically made of silicon. A bottom integrated circuit (IC) passivation layer 130 is fabricated over the substrate 106. The bottom IC passivation layer 130 can be fabricated from silicon dioxide. A heater 132 is typically fabricated within the bottom IC passivation layer 130. The heater 132 can be buffered by a pillow 134 as illustrated. The pillow 134, made of for example gold, buffers the heat generated by the heater 132. The heater 132 and the pillow 134 are proximal to the static bubble drum 124, the switching chamber 126, or both. The heater 134 provides heat to the static bubble drum 124, the switching chamber 126, or both, the heat causing the expansion of the inactive static bubble 122 as discussed herein above.
The switching chamber 126, the static bubble drum 124, and the quenching pipe 128 are generally located above and connected to a fluid filled layer 136. The index matching fluid is generally present in these chambers except as displaced by the inactive static bubble 122. As already illustrated and discussed, in the inactive state, the static bubble drum 124 contains the inactive static bubble 122, therefore a majority of the fluid within the static bubble drum 124 is displaced by the static bubble 122. In the active state, the static bubble drum 124 and the switching chamber 126 are filled with the active bubble 122 x of FIG. 2B. A top structural layer 138 covers and encloses the switch 102. For example this layer 138 can be fused silica.
From the foregoing, it will be apparent that the present invention is novel and offers advantages over the current art. Although the specific embodiment of the invention is described and illustrated above, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. For example, differing configurations, sizes, or materials may be used to practice the present invention. The invention is limited by the claims that follow. In the following, claims drafted to take advantage of the “means or steps for” provision of 35 USC section 112 are identified by the phrase “means for.”

Claims (21)

What is claimed is:
1. An optical switch comprising:
a static bubble drum adapted to contain a static bubble; and
a switching chamber connected to said static bubble drum, said switching chamber adapted to allow the static bubble to expand into said switching chamber.
2. The optical switch recited in claim 1 further comprising a heater proximal to said static bubble drum.
3. The optical switch recited in claim 2 wherein said heater is proximal to said switching chamber.
4. The optical switch recited in claim 2 wherein said heater comprises a resistor.
5. The optical switch recited in claim 2 further comprising a pillow proximal to said heater.
6. The optical switch recited in claim 1 further comprising a quenching pipe connected to said switching chamber.
7. The optical switch recited in claim 6 wherein said quenching pipe has a diameter generally ranging from 10 microns to 20 microns.
8. The optical switch recited in claim 1 wherein said static bubble drum has a diameter generally ranging from 20 microns to 60 microns.
9. The optical switch recited in claim 1 wherein said switching chamber has a width generally ranging from 10 microns to 20 microns.
10. An optical switch array comprising a plurality of optical switches wherein each of said optical switches comprises:
a static bubble drum adapted to contain a static bubble;
a switching chamber connected to said static bubble drum, said switching chamber adapted to allow the static bubble to expand into said switching chamber; and
a heater proximal to said static bubble drum.
11. The optical switch recited in claim 10 wherein said heater is proximal to said switching chamber.
12. The optical switch recited in claim 10 wherein said heater comprises a resistor.
13. The optical switch recited in claim 10 further comprising a pillow proximal to said heater.
14. The optical switch recited in claim 10 further comprising a quenching pipe connected to said switching chamber.
15. The optical switch recited in claim 14 wherein said quenching pipe has a diameter generally ranging from 10 microns to 20 microns.
16. The optical switch recited in claim 10 wherein said static bubble drum has a diameter generally ranging from 20 microns to 60 microns.
17. The optical switch recited in claim 10 wherein said switching chamber has a width generally ranging from 10 microns to 20 microns.
18. The method for switching optical signals, the method comprising heating a static bubble drum to expand a static bubble from said static bubble drum into a switching chamber connected to said static bubble drum thereby changing optical properties within the switching chamber.
19. The method recited in claim 18 further comprising heating said switching chamber.
20. The method in claim 19 further comprising buffering said heat with a pillow.
21. The method in claim 18 further comprising removing the heat from said static bubble drum to allow contraction of said static bubble back into said static bubble drum.
US10/288,675 2002-11-05 2002-11-05 Optical switch with static bubble Expired - Fee Related US6707592B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/288,675 US6707592B1 (en) 2002-11-05 2002-11-05 Optical switch with static bubble

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10/288,675 US6707592B1 (en) 2002-11-05 2002-11-05 Optical switch with static bubble

Publications (1)

Publication Number Publication Date
US6707592B1 true US6707592B1 (en) 2004-03-16

Family

ID=31946557

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/288,675 Expired - Fee Related US6707592B1 (en) 2002-11-05 2002-11-05 Optical switch with static bubble

Country Status (1)

Country Link
US (1) US6707592B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050018956A1 (en) * 2003-07-23 2005-01-27 Tyler Sims Clean and test for fluid within a reflection optical switch system
GB2411487A (en) * 2004-02-25 2005-08-31 Agilent Technologies Inc Optical switch with heat-created bubble

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4988157A (en) 1990-03-08 1991-01-29 Bell Communications Research, Inc. Optical switch using bubbles
US5699462A (en) * 1996-06-14 1997-12-16 Hewlett-Packard Company Total internal reflection optical switches employing thermal activation
US6188815B1 (en) 1999-07-07 2001-02-13 Agilent Technologies, Inc. Optical switching device and method utilizing fluid pressure control to improve switching characteristics
US6212308B1 (en) 1998-08-03 2001-04-03 Agilent Technologies Inc. Thermal optical switches for light
US6327397B1 (en) 2000-02-22 2001-12-04 Agilent Technologies, Inc. System and method for providing temperature control for a thermally activated optical switch using constant total power
US6360775B1 (en) * 1998-12-23 2002-03-26 Agilent Technologies, Inc. Capillary fluid switch with asymmetric bubble chamber
US20030012483A1 (en) * 2001-02-28 2003-01-16 Ticknor Anthony J. Microfluidic control for waveguide optical switches, variable attenuators, and other optical devices

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4988157A (en) 1990-03-08 1991-01-29 Bell Communications Research, Inc. Optical switch using bubbles
US5699462A (en) * 1996-06-14 1997-12-16 Hewlett-Packard Company Total internal reflection optical switches employing thermal activation
US6212308B1 (en) 1998-08-03 2001-04-03 Agilent Technologies Inc. Thermal optical switches for light
US6360775B1 (en) * 1998-12-23 2002-03-26 Agilent Technologies, Inc. Capillary fluid switch with asymmetric bubble chamber
US6188815B1 (en) 1999-07-07 2001-02-13 Agilent Technologies, Inc. Optical switching device and method utilizing fluid pressure control to improve switching characteristics
US6327397B1 (en) 2000-02-22 2001-12-04 Agilent Technologies, Inc. System and method for providing temperature control for a thermally activated optical switch using constant total power
US20030012483A1 (en) * 2001-02-28 2003-01-16 Ticknor Anthony J. Microfluidic control for waveguide optical switches, variable attenuators, and other optical devices

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050018956A1 (en) * 2003-07-23 2005-01-27 Tyler Sims Clean and test for fluid within a reflection optical switch system
US7274840B2 (en) * 2003-07-23 2007-09-25 Avago Technologies Fiber Ip (Singapore) Pte. Ltd. Clean and test for fluid within a reflection optical switch system
GB2411487A (en) * 2004-02-25 2005-08-31 Agilent Technologies Inc Optical switch with heat-created bubble
GB2411487B (en) * 2004-02-25 2006-11-08 Agilent Technologies Inc Optical switch

Similar Documents

Publication Publication Date Title
US6487333B2 (en) Total internal reflection optical switch
JP4330197B2 (en) Total internal reflection optical switch with vertical fluid filled hole
JPH11287962A (en) Switching element
US20090016674A1 (en) Silicon structure and method of manufacturing the same
US6327397B1 (en) System and method for providing temperature control for a thermally activated optical switch using constant total power
US6707592B1 (en) Optical switch with static bubble
US6509961B1 (en) Optical cross-switch signal monitoring method and system therefor
JP2003149564A (en) Pressure-actuated bi-stable optical switch
US6925232B2 (en) High speed thermo-optic phase shifter and devices comprising same
US20080160676A1 (en) Heat Transfer Structures
US6876788B2 (en) Preventing hydrodynamic crosstalk in an optical switch
US6895139B2 (en) Bistable thermopneumatic optical switch
US6532319B2 (en) Ceramic substrate for photonic switching system
US6718085B1 (en) Stable optical switch with reduced power consumption
US6904192B2 (en) Latching bubble for fluid-based optical switch
US7221819B2 (en) Operating an optical switch at a negative pressure differential
US7024062B2 (en) Optical switch with low pressure bubble
JP3749932B2 (en) Efficient thermally activated optical switch and method of manufacturing the same
JP2004139080A (en) Optical switch for changing light path and its operating method
WO2001048532A2 (en) Integrated planar optical waveguide and shutter
JPH11258529A (en) Waveguide-type optical switch
US20050092233A1 (en) Single and multi-layer crystalline structures

Legal Events

Date Code Title Description
AS Assignment

Owner name: AGILENT TECHNOLOGIES, INC., COLORADO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SCHROEDER, DALE W.;UEBBING, JOHN J.;REEL/FRAME:013494/0687;SIGNING DATES FROM 20021101 TO 20021106

AS Assignment

Owner name: AVAGO TECHNOLOGIES GENERAL IP PTE. LTD., SINGAPORE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AGILENT TECHNOLOGIES, INC.;REEL/FRAME:017207/0020

Effective date: 20051201

AS Assignment

Owner name: AVAGO TECHNOLOGIES FIBER IP (SINGAPORE) PTE. LTD.,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.;REEL/FRAME:017675/0199

Effective date: 20060127

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20120316

AS Assignment

Owner name: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD

Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE NAME OF THE ASSIGNEE PREVIOUSLY RECORDED ON REEL 017207 FRAME 0020. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:AGILENT TECHNOLOGIES, INC.;REEL/FRAME:038633/0001

Effective date: 20051201